http://mpex.com/
use to carry battery doors for Super Graphics for $40. Call them and ask for the Large Format department.

Alternative: Refer to http://www.southbristolviews.com/pics/Graphic/manual-pdf/servicemanual.pdf
Remove the top RF cover.
Accurately measure the battery door opening.
Get a piece of ABS plastic or acrylic, cut it 3/32 to 1/8 inch longer than the opening.
Trim the outside edge down so that the piece will fit under the edge of each side.
Correct fit will allow the door to slide to one side just enough to allow the other to clear the housing when installing or removing.
A piece of spring metal can be bonded to the back side to ensure a secure fit if needed._________________The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.